I have recently switched to DADGAD tuning, before that I was using light tension strings ( 12 16 24 32 42 53 ).
But because of DADGAD, to compensate for the lack of tension on the neck, I wanted to switch to a mix of medium and light strings, puting higher tension strings on the ones that are lowered, resulting in ( 13 17 24 32 42 56 ), some friends playing DADGAD even used 14 and 18 for the two higher strings.

I wondered what you DADGAD players used?

And of course the economic side of it, buying one light set and one medium set and throwing away half the strings is not a very good solution, do you have any DADGAD-ready set to recommend?

When I played in DADGAD tuning, it was one of several tunings I would use, so it never crossed my mind to use different strings. But if this is something you want to do, I'd suggest constructing your own custom set with single strings rather than buying two sets and discarding the extra strings.

Just Strings sells individual strings from a variety of manufacturers. Maybe you can find the brand you like in this list from their site.